Posted: 24/09/2016 at 08:34
Watercress works in still ponds too Wendy. I've had both
It has to be warm enough for it to root, but once it does, it hoovers up the nutrients and makes a big difference. I used it in the smaller pond at my last house - the other one would have needed a watercress farm to eradicate the blanket weed! It's about balance though - the big pond did it's own thing.
Re your brown/oily situation Jo - is there something in the surrounding soil leaking in? Do you have a liner or is it a clay lined pond? If the pond's new, it may still be settling in